Lightweight metal sheets are known from the prior art and preferably comprise at least two metallic outer layers, between which at least one nonmetallic core layer is arranged. In spite of their low weight, such lightweight metal sheets have high local stiffness and are able to provide effective sound damping. Many applications require that these lightweight metal sheets can be connected to other sheet-metal parts or components. However, the joining methods that are often used for metal sheets, such as fusion welding or soldering, cause problems on account of their high heat input. The reason for this is that a thermoplastic material is preferably used as the plastic for the core layer, which has the effect that the core layer produced from this plastic melts during joining, or is damaged in some other way.
It is therefore advantageous for connecting a lightweight metal sheet to another component to provide a frictionally engaging and/or interlocking connection via an opening in the lightweight metal sheet by using a connecting element, such as a screw or a rivet. On account of the flow behaviour of the non-metallic core layer, preferably consisting of plastic, this cannot however ensure lasting strength of the connection. One cause for this can be seen in a decreasing holding force over time, on account of the flow behaviour. As a consequence, the connection between the lightweight metal sheet and the component, for example a metal sheet, loosens.